Residential gateways (RGs) such as a PacketCable® (PC), a registered trademark of CableLabs, embedded multi-media terminal adapter (eMTA) or a stand-alone multi-media terminal adapter (sMTA) may not possess the resources required to support a conference call. Conferencing can be performed either within an RG or a conference bridge. Many deployments will not use a conference bridge for reasons of cost. Also, due to costs, an RG may not be able to support conferencing in some or all cases. Current two-line products cannot support three-way conference calls and busy line verification on both lines at the same time. Four-line products raise even more issues. It is also desirable to provide subscribers the ability to support conference calls having a larger number of participants.
The industry has struggled with this problem which may be characterized as a trade-off between more digital signal processor (DSP) power and DSP memory on the one hand and reducing cost on the other hand. Generally the problem has been addressed by either providing a more powerful communications gateway (CG) or providing a CG that is not able to meet all requirements in the worst case situation. The terms RGs and CGs described above and utilized herein are interchangeable and their design and functions are substantially the same especially with reference to the present invention.
FIG. 4 illustrates a communication network 10 which may employ the present invention to great advantage. Each network user has a Communication Gateway (CG) 141 to 14m (14), as shown in FIG. 1. The CGs 14 interface user equipment, such as telephones 121 to 12n (12) and computer modems, with the rest of the network. The CGs 14 are connected to an internet protocol (IP) network through a Cable Modem Termination System 16 (CMTS).
To handle the overhead functions of the IP network 18, a network management system 22, an Operations Support System (OSS) 24 and a call management system 20 are used. The Call Management System 20, “Call Agent”, controls telephony calls sent through the network 18.
The IP network is connected to the public switched telephone network (PSTN) 28 via an IP network/PSTN gateway 26. The IP/PSTN gateway 26 acts as the interface between the IP network 18 and the PSTN 28 or other networks.
The simplified hardware of a CG 14 is shown in FIG. 5. The CG 14 has an RF connector 32 to receive RF signals from and transmit RF signals over the network 10. A tuner/amplifier 34 and a cable modem 36 are used to convert the received RF signals into digital baseband signals and digital baseband signals into RF signals for transmission. The CG 14 also has a digital signal processor (DSP) 38 and codec 44 for processing voice signals. The DSP receives calls from the network and passes them to a TT 12, for example, through CODEC 44. Conversely, the CODEC 40 transfers calls to the network from the associated TT12 through the DSP 38. A processor 42 along with a random access memory (RAM) 44 and non-volatile memory (NVMem) 46 are used to perform various functions of the CG 14.
The simplified hardware of a Call Management System 20 is shown in FIG. 6. The Call Management System 20 comprises a Call Agent. The Call Agent 48 controls various functions of the Call Management System 20 and interacts with other modules 22,24. Call signaling 50 sends commands to control components of the network, such as the CGs 14. Other components of the Call Management System 20 for use in performing its functions are the communications stacks 52, network interface module (NIM) 54, processor 58, RAM 60, NVMem 62 and permanent storage 56.